Prevalência de Trypanosoma cruzi (Chagas, 1909) e T. lainsoni (Naiff & Barrett, 2013) em roedores e marsupiais do bioma Cerrado e efeitos do parasitismo sobre a saúde de populações destes animais

Abstract

Non-volant small mammals are important hosts and/or reservoirs of parasites of the genus Trypanosoma. Aiming to know the trypanosomes of these animals in Triângulo Mineiro and Alto Paranaíba (MG, Brazil), 294 animals were captured (117 Rhipidomys macrurus, 54 Hylaeamys megacephalus, 15 Oecomys cleberi, one Rattus rattus, 85 Gracilinanus agilis and 22 Didelphis albiventris). Blood smears were prepared for each animal, and the blood was also placed on filter paper. The DNA extracted from blood on filter paper was submitted to Nested-PCR targeting the 18S rRNA gene of Trypanosoma spp., and the positive samples were sequenced. Additionally, we also sought to verify the effects of T. lainsoni on the neutrophil:lymphocyte ratio (N:L) and body condition of populations of G. agilis (n=75) and R. macrurus (n=108). For this, body condition data, measured by the scaled mass index, and the N:L ratio, obtained by the differential count of leukocytes in blood smears, were used in the elaboration of generalized linear models. Models with AICc>>2 values were considered plausible. The blood smears showed 7% (21/294) of trypomastigotes forms, mainly those of G. agilis (12/294, 4%), which also exhibited the greatest parasitemia. Regarding Nested-PCR, 32% (68/215) of the samples were positive, including R. macrurus, H. megacephalus, D. albiventris and G. agilis. Of the sequences obtained, 82% (56/68) were similar to T. lainsoni and 10% (7/68) to T. cruzi TcI. This is the first report of T. lainsoni parasitizing R. macrurus and the second for H. megacephalus, as well as the first description of T. cruzi TcI in R. macrurus. Model analysis suggests that the presence of T. lainsoni does not influence the body condition of G. agilis and R. macrurus (AICc=4.99 and 2.05, respectively), also not affecting the N:L ratio of G. agilis (AICc=3.56) and showing discrete effects on this parameter in R. macrurus (AICc=2). With these findings, we concluded that T. lainsoni is a non-pathogenic generalist parasite with a wider distribution than previously known. Furthermore, the low species diversity and/or abundance of highly competent reservoirs (such as D. albiventris) contribute to the maintenance of the sylvatic cycle of T. cruzi TcI.